The present invention relates to an underwater cleaning apparatus for cleaning and removing substances adherent to vessels or structures (hereinafter referred to as cleaning object) submerged in seas or lakes, etc.
Vessels and the like require cleaning either periodically or whenever a need arises to remove various living things such as seaweeds and shells or contaminants such as oil for the sake of appearance and proper performance. Divers were conventionally employed to manually remove them one by one using a scraper as one means to remove such substances. Such manual operation is, however, extremely inefficient, involving great amounts of time and labor especially for large ships.
Various cleaning apparatuses have been proposed such as shown in schematic views of FIGS. 1 and 2 to overcome above mentioned problems (for instance, Japanese Utility Model Application No. 32107/1978). An underwater cleaning apparatus 100 shown in FIGS. 1 and 2 comprises a main body 100A and cylindrical outer shells 101, 102 and 103 on both sides of the rear and at the center of the front of the main body 100A, respectively. Impellers 104 to 106 are concentrically provided inside the cylindrical outer shells 101 to 103, so that the bottom surface of the main body 100A is pressed against the cleaning object by the propulsion of the impellers 104 to 106 as they are driven to rotate. Three wheels 110 to 112 are provided at the bottom of the main body 100A, by steering the wheel 110 at the back end toward the direction of either left L or right R, the underwater cleaning apparatus 100 can be manipulated in any arbitrary direction. Cleaning brushes 107 to 109 are also provided at the bottom concentrically with the impellers 104 to 106 to remove substances adherent to the object. The cleaning brushes 107 to 109 are rotated as the impellers 104 to 106 are actuated so as to remove substances adherent to the object. The impeller 104 in the outer shell 101 and the cleaning brush 107 rotates in a direction opposite to the rotational direction of the corresponding impeller 105 in the outer shell 102 and the cleaning brush 108. The impeller 106 and the cleaning brush 109 in the outer shell 103 at the front rotate in the direction of either L2 or R2. For convenience, levers 114 are provided on the main body 100A for controlling and manipulating the cleaning operation as well as a railing 115 for operators to hold. On top of the outer shells 101 to 103, baskets 101A to 103A are attached to hold substances collected by cleaning operation.
With such as construction, the underwater cleaning device 100 is operated by manipulating the lever 114. Since its direction of advance is controlled by steering the wheel 110 on the rear side, the direction cannot be changed on the spot without turning it around in arc. When the wheel is steered, it becomes necessary to manipulate the lever 114 to restore its original position if the apparatus is to move straight ahead. Further, since there are an odd number (3 in this case) of impellers 104 to 106 with the cleaning brushes 107 to 109 connected thereto, the overall balance of the apparatus is difficult to be maintained despite of the efforts to maintain the balance by rotating the outer shells 101 and 102 at the back in opposite directions. This is because impellers 106 and the cleaning brush 109 in the outer shell 103 at the front must always rotate in the direction of either L2 or R2. With the conventional apparatus, the cleaning brushes 107 to 109 are fixed to the impellers 104 to 106, respectively. Although this poses no problem when cleaning a flat surface, cleaning of an irregular surface becomes difficult because the brushes per se are incapable of making vertical movement and may clash with the surface of the object depending on the position of the underwater cleaning apparatus 100 or cause themselves or the object surface to be damaged. There is provided no means to adjust the buoyancy or the posture of the main body 100A in the conventional cleaning apparatus 100. Thus, the buoyancy of the cleaning apparatus 100 may greatly vary depending on whether the water is fresh or brine, preventing smooth operations. The apparatus may become unbalanced depending on the direction or the posture of operation. It also poses problems in respect of energy consumption as it requires great force in manipulation. As the main body 100A is substantially circular in plan view, it was difficult to remove adherent substances from the corners of the object.